Optical data storage media for bit-wise recording of a microhologram using an incident radiation at a wavelength of about 405 nm are provided. The optical storage medium includes (a) a non-photopolymer polymer matrix; (b) a non-linear sensitizer comprising a phenylethynyl platinum complex, wherein the non-linear sensitizer is capable of triplet-triplet energy transfer from an upper triplet state (Tn) of the non-linear sensitizer to a lower triplet state (T1) of a reactant, wherein “n” is an integer greater than 1; and (c) a reactant capable of undergoing a chemical change upon the triplet-triplet energy transfer from the non-linear sensitizer, thereby causing a refractive index change in the medium to record the microhologram.